Field of the Invention
The present invention relates to a semiconductor device and a method for manufacturing the same.
Description of the Background Art
A technique using a deep trench isolation (DTI) structure has been heretofore known as a method of isolation for a semiconductor device. In the isolation method, an insulating film is formed on the inner surface of a deep trench for the DTI structure to have an isolation function.
Semiconductor devices including such a DTI structure are described in, for example, Japanese Patent Laying-Open Nos. 2000-269317 and 2011-71304. In these two documents, an oxide film is formed on the sidewall of a deep trench using an oxidation technology, and then a tetra ethyl ortho silicate (TEOS) oxide film is formed using a low pressure-chemical vapor deposition (LP-CVD) technology.